An advertisement for a portable electrical generating unit claims that the unit's diesel engine produces 28,000 hp to drive an electrical generator that produces 30 MW of electrical power.
I seriously doubt that such a powerplant is 'portable', unless it is mounted on a naval vessel.
No it isn't possible. The output of the diesel engine is only 20.8 MW and it isn't possible for a generator to produce more power than is given to it. The 20.8 comes from the fact that 1HP 746W